According to Limper [32], due to its low boiling point,
alcohol, which is attached to the TESPT coupling agent, can
be classified as a Volatile Organic Compound (VOC). During
curing, the ethanol in the ALK is released, and the amine
group becomes reactive and forms coupling bonds with the
silanol Si–O group of silicas, instead of the non-polar hydrocarbon
of ALK interacting physically through moment
dipole interaction with the long chains of NR. By this
mechanism, the silica-ALK-NR bonding/interaction is
formed, and the probable mechanism for such an interaction
is presented in Fig. 12